EASA AD US-2018-04-07
Wings - Structural Significant Items (SSIs) - Revision of the Maintenance or Inspection Program / Inspection
Summary
The Federal Aviation Administration's Airworthiness Directive 2018-04-07 titled 'Wings - Structural Significant Items (SSIs) - Revision of the Maintenance or Inspection Program / Inspection' applies to all Boeing Model 747 series airplanes including 747-100, 747-200, 747-300, 747-400, 747SR, and 747SP variants. This directive addresses fatigue cracking issues identified in aging transport category airplanes by requiring updates to maintenance and inspection programs to include inspections of structural significant items (SSIs).
What Changed
This new airworthiness directive introduces mandatory revisions to the maintenance or inspection programs for the affected Boeing 747 models to incorporate inspections that meet or exceed the required damage tolerance ratings for SSIs. It mandates repetitive inspections to detect cracks in all SSIs and requires reporting any cracks found to Boeing. Additionally, repairs must be performed if cracks are detected to ensure structural integrity.
Why It Matters
This directive is critical for aviation professionals as it ensures the continued structural safety of aging Boeing 747 aircraft by proactively identifying and addressing fatigue cracking in key structural components. Operators and maintenance organizations must comply to prevent potential structural failures, maintain regulatory compliance, and uphold airworthiness standards. The reporting requirement also helps Boeing evaluate the effectiveness of supplemental inspections and improve future maintenance guidance.
What To Do
Operators of affected Boeing 747 series airplanes must revise their maintenance or inspection programs by March 30, 2018, to include the specified inspections for SSIs. They must conduct repetitive inspections to detect cracks and repair any found damage as necessary. All cracks involving SSIs or related nearby structures must be reported to Boeing to support ongoing structural evaluation.
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